Kiln.



Patented Jan. 15, 11918.

J. L. HARPER..

KILN.

Armenian man APR. 29. 19m. nennen Die. l. |911.

` 5| wlw/nto@ commu-4 A r///l ment are subjectedljtoffh" h tem tance that the atmosphene of t 'tenancc in kilns' of this t 'UNITED' STATES PATENT OFFICE.

.Term L HABPEB., or NIAGARA FALLS, NEW Yoan..

KILN.

specimaoummnrmn. Patented Jan. 15, 1918.

appuu'ou inea anni as, 1910,- sria1-no.,ss,4v4'. rit-nena December 1, .1917. serial no. 204,990.

To all 'whom it may concern;

Be it known that I,.JOHN LQHhninn, a

Acitizen of the United Statesxresiding at` Niagara Falls, in the county of Nia ara and Sta-fe of New York,- have inv'en certain new and useful I i/iiprovem-ent's in Kilns,` of which the' following is a specification.

M v invention relates .to a method-and ap- 'paratuafor the treatmentfof materials or articles which thetcourse of such treatratures'l The ,process 1s' 'particular y app icable in electrica-l1 heated kilns ofjthe 'kind shown in U. S. atent'iNo, 925 902, ,granted -June `lfnirkworthy. In auch in which the heat-is gen- `of an electrical c urrent' through resistors, it has been found that temperatures of almost any degree may be produced, such temperatures being attainable-in combustion furnaces only when the llame is oxidizin in characte.

f The present invention relates to themanof an desired atmosphere'by the int uction o suitable ses, whether such gasesare neutral, re

ucing, carbo ter, or of such other character as may enable the production of anyA desiredeifect on the materials being treated.

Thus in the manufacture of various forms of pottery articles it is of a hilghest impore mules or kilns in which the.a.rticles are burned shall be'of .the proper character. In the burning of certain porcelains, where 4temperatures as high as 2200" F., must be used, it is essential that a reducing atmosphere should 'be maintained- So also in'the firing of articles which have lazes containing metallic coloring ingredients, such as silver or copper compounds, it is necessary to have the atmosphere of the kiln under control, as the color of` the finished productdcpends upon the state of oxidation-of the metals -in the glaze. In the lirin of other classes of pottery articles,in w ich metallic oxids are used as coloring materials .in the glaze, it is important that the atmosphere should not be redueiug in character but'should be'neutral or even oxidizing.

In the heat treatment of metals, such asl iron or steel, which are readily oxidizable at high temperatures, such oxidation can readily be obviated by introducing suitable neutral or non-oxidizing gases into the kiln.

nizing, or oxidizing in charac- -Or when iron Aor steel'` articles are to b e cur-A (burized, as in the manufacture of armor kilns in the presence of a suitable :itunesphere, such atmosphere bein produced by displacing the air which wilgl be normally 'present in the kiln, by such gases as pro- 4ducer gas, d eoxidized air or nitrogen, hydrocarbon gases or other gases b which it is desired to produce some chemical or physical efectupon thematerial being treated.

This process may becarricd out. in thc kiln such as is shown in the accompanying drawings, 'in which:

Figure 1 is a longitudinal vertical section of n. portion of the kiln;

Fig. 2 is a transverse vertical section on the line C-C of Fig. 1;4 and Fig. 3 is a transverse vertical section ou lines D--D of` Fig. 1.

The furnace shown in Ithe drawings is of the type illustrated in the patent before rcferred to, and consists'of a long tunnel provided with a double truck on which trains of cars can he; moved in opposite direction.,

these earsibcig preferably of the construc-y tion illustrated in the patent. above referred to. 'lhcse curs have :lt each end upwardly extending walls which divide the tunnel into :i series of chambers. The general mode of operation of the present device is the sumo. us that described in that: patent.

Considering now thc chamber in the middie of the tunnel, the gus is introduced from V:my suitable source of-supply through the flue 1 whence it passesto the Hue 2, longitudinally arranged' within the" wall of the furhucc, und hence into the transverse. lines 3, 3 arranged in the roof of the kiln, from which flues 'the gases pass into the furnace chamber proper. It will he noted that the arrangement of {luc-s is such that the entering gases will be heated by contact with the walls' and roof portion of thejurnace prnc.

lbcrs.

The entrance flue 1 and the exit fines 5, 5 ure-cach provided with dempers 10, 11', so that the rapidity of flow of thegases through the furnace can be controlled. An additional as supply for each chamber may be provided as'shown in Fig. 3 by connecting the gas supply with the entrance flue 6 which is connected with the lflues 7, 7 and transverse-hues 8,' 8 in the same manner as llLheret/ofore described for the central chamber. R, R are electrical heating resistors.

@nl three chambers have beenshown as provi ed w'ltlr`a gasI supply, but it is of course. obvious that as many of the chambers in the series, usually thirteen, may be similarly connected to' the gas supply, and that by a proper arrangement of conduits, the

same gas supplymay'be connected to as many chambers as desired.

A suitable apparatus, such as a pump or blower, for forcing the gases into the furnace and exhausting them therefrom may of course be provided if desired.

In operation, the materials to be treated are placed on the cars, and are gradually heated as they progress toward the middle chamber-of the furnace where they are subjected to the intense heat radiated from the resist-or R. While being so heated they aresubjected to the actions of the gases introduced into the kiln chambers in .the manner Y above described.

While I have described the operation particularly in connection with a kiln of the kind shown in the patent above 'referred to,

I I do notl of course wish to be limited to this particular type of electrically heated kiln, as manifestly kilns of other construction may be used to carry out my process, as long as the articles are heated by radiation from electrically heated resistors and are maintained in a redetermined atmosphere of the kind described. y

It is also apparent that the introduction of gases. of a predetermined composition may serve to wash or force out of the furnace any other g'ases that may be in the furnace, thereby eliminating the detrimental effects of such 'gases on the wares being' treated. v"

What I claim is:

1. A tunnelkiln having the median Imrtion thereof provided with an electrical' heating means, flues4 for introducing gases into such median portion and means \for forcing gas into said flues.

2. A tunnel kiln provided with electrical resistors for heating-the same located at its median portion, flues for introducing gas into the furnace at such median portion, andv exit flues from the kiln arranged at both Y sides of such median portion, whereby the kiln may be filled with an atmosphere of In testimony whereofv` I aix my-sighature in presence of two witnesses.

, JOHN L. HARPER. Witnessesz.

BENJAMIN F. LEE, J. M. N, BINNEY. 

